Since 1 April, for every 100 print books sold on Amazon.com, 105 Kindle eBooks have been shifted. And, like with in the UK, this includes print editions that are yet to be available digitally.

In addition, in the US, Amazon has sold over three times as many eBooks in 2011 than it did in the equivalent period last year. And, thanks to these figures, the company now boasts the fastest ever year-in-year growth rate for its books business, in both units and dollars.

Amazon.com now carries more than 950,000 Kindle titles, with over 175,000 of them being added in the last five months alone. That's a good 300,000 more than the UK, although the American store has been running over three years longer.

How long will it be before publishers switch to digital only, we wonder?

What do you think? Does this signal the death knell for print publishing? Let us know your thoughts in the comments below...